Fuel burner for tobacco curing



Aug 5, 1958 A. Y. DOWELL ETAL 2,845,999

.. FUEL BURNER FoR TOBACCO cuRING Filed Deo. 4, 1952 INVENTORS A.' YATEs D'owELL` D. s. EATON ates Pate.;

FUEL BURNER FR TOBACCO CURING Alvis Yates Doweli, Washington, D. C., and Donald G. Eaton, Arlington, Va.

This invention relates to the curing of tobacco or other products, and particularly to a eurer or heating `structure which can be placed in a barn or building in which tobacco or other substance is to be cured, and operated to provide the necessary heat for the` curing process.

Various and sundry types of tobacco curers have been proposed, some of which have been employed in the curing of tobacco. All of these devices have been subject to criticism for one reason or another, and consequently have not been fully satisfactory.

In the curing of tobacco in a barn or similar structure it is customary to start with a Vlow heat and gradually to increase the heat until the tobacco has reached the desired condition, or the curing has been completed. Due to the various conditions, including the characteristics of the product to be cured, the amount of such product, the equipment employed, the area to be heated, the character ofthe fuel, and the like, provision of a curer which would satisfactorily perform the function for which it was designed has been a problem through the years, and often has resulted in the improper curing and inferior end products.

It is an object of the present invention to solve these and other problems by providing a tobacco eurer of relatively simple and inexpensive structure which can be easily produced from readily available material, which requires no skill in its operation, and which will satisfactorily perform the function for which it was created.

Another object of the invention is to provide a tobacco curer in which both the fuel and the air from the exterior of the barn in which the device is used are appropriately preheated 'to obtain maximum efficiency of operation and economy of fuelv consumption.

A further object of the invention is to provide a combination air and fuel preheating means which can be easily and inexpensively produced, which will provide good metal to metal contact with heated portions of the device as Well as to maintain the burner and downdraft air tube in the proper assembled relation.

A further object of the invention is to provide a tobacco curer which may have an upright or horizontal casing with the burner disposed in the lower portion of the same, with air for supporting combustion introduced through a downdraft tube, and with the fuel and the air for supporting combustion preheated selectively, and including a helical member normally of slightly larger Adiameter than the interior of the air intake tube, which When inserted into such tube will fit tightly within and have good metal to metal contact with such tube to avoid the necessity of Welding or using mechanical means for fastening the coil within the tube.

Further objects and advantages of the invention will be apparent from the following description taken in conjunction with the drawings, wherein:

Figure l is a vertical section illustrating the invention applied to an upright casing with an air preheating coil in the downdraft tube;

Fig. 2, a fragmentary vertical section illustrating the invention applied to a horizontal casing and with both air and fuel preheating coils in the downdraft tube;

Fig. 3, a part side elevational, part vertical sectional view of a structure similar to that of Fig. 2, but with only the` air preheating coil in the downdraft tube;

Fig. 4, a fragmentary vertical section with only the fuel preheating coil within the downdraft tube.

Briefly stated the present invention comprises either an upright or a horizontal casing in which a burner is located. Air Within the casing is heated by the combustion of fuel from the burner, With oxygen supplied to support combustion by means of a downdraft tube which terminates in slightly spaced relation above the top of the burner.

The present invention contemplates the supply of fuel to the burner through a supply line which has a preheating coil subject to the heat of the fuel consumed within the casing.

The invention also contemplates the preheating of air through a downdraft tube and the lengthening of the path through which the air flows inits passage from one end of the tube to the other. Such lengthening of the path of llow of the air is accomplished by means of one or more spiral ribbons or coils which provides a baflle or indirect path of ow within the downdraft tube, such bafiles within the downdraft tube preferably being of slightly larger size than the tube so that it is contracted when it is inserted into the downdraft tube and due to its resiliency or springiness it will provide a relatively tight joint between the spiral bathe and the wall of the downdraft tube.

The invention further contemplates that the spiral bfe for the air passing through the downdraft air Itube be of a strip of metalv and in addition a coil of pipe through which also fuel may be supplied to the burner as shown in Fig. 4, or if preferred instead of two baffles, either may be used as shown in Figs. 3 and 4.

With the fuel preheated by the provision of a fuel line coil within the downdraft tube or the air preheated by the provision of a spiral ribbon in the downdraft tube, as just described, either the coil or the spiral ribbon may be employed for maintaining the proper location between the downdraft tube and the burner. This can be accomplished by a slight reduction in the diameter of the extremity of the ribbon or coil in each case and the end of the same applied directly to the burner. In one case the reduced spiral portion may engage the burner with .a tapering end as shown in Fig. 2 or it may t about a conical projection on the top of the burner as illustrated in Fig. 1. In Fig. 2 both the fuel coil and the spiral ribbon for increasing the path of the air flowing downwardly through the air intake are shown together. They are Ashown separately, however, in Figs. 3 and 4. In Fig. 3 the spiral air bailie is employed without the preheating fuel coil and serves to maintain the burner and the air intake pipe in proper relation while in Fig. 4 only the preheating coil for the fuel is disposed in the downdraft tube and the lower end of this coil has a tapered end and friction tit with the burner as shown in Fig. 2. It will therefore be understood that the present invention contemplates the various factors which have to be taken into consideration in providing a satisfactory burner.

With continued reference to the drawings and particularly Figs. 1 and 3 the present inventiOn contemplates either an upright casing 10 as shown in Fig. 1 or horizontal casing 11 as shown inl Figs. 2, 3 and 4, the po sition of the casing being secondary in importance. When the casing is in upright position it may be of seamless construction or where it is of a horizontal character it may be longitudinally divided and have ears 12 and 13 fastened together by means of bolts 14 and nuts 15.

With the casing in horizontal position it may be supported by a cradle 16 attached by rivets 17 to the lower section of the casing. Also the horizontal casing of Fig. 3 may be provided with an end 18 having perforations 19 for the inlet of air heated by the device.

The casing of Fig. l may likewise be provided with a bottom 20 held in place by rivets Z1 and having perforations 22 for the admission of air to be heated. With the structure of Fig. 1 a base 23 may be provided on which the casing 10 is mounted.

Within the bottom of each casing it) and 11 is a burner consisting of a base 24 and a cap 25 provided with inclined divergent burner openings or ports 26 through which the fuel ows to be burned. The base 24 is' provided with an upright extension having an externally threaded portion 27 and an unthreaded portion of slightly smaller diameter. Likewise the ICapZ-S has an internally threaded portion which receives the threads 27 of the base and the cap has a portion of slightly less diameter which snugly receives the extension of the portion of the base. Thus the ports 26 may be enlarged or reduced in size by the telescoping of the portion of the base within the receiving portion of the bore.

The burners of Figs. l and 3 are identical each being provided with an upstanding conical boss or projection 31. This conical projection may be employed as a guide or centering device as will be hereinafter described.

The burners of Figs. 2 and 4 are identical with those of Figs. l and 3 except that instead of the boss 31, the burners of Figs. 2 and 4 do not have such a boss but have a tapering opening 32 for frictionally receiving a fuel line later to be described. The burners of Figs. 2 and 4 are held in position by rivets or fasteners 33 instead of by the nipple 34 of the fuel line. With the burners 0f Figs. 1 and 3 fuel is supplied from a fuel line435 through the nipple 34 threaded through the bottom of the burner as illustrated best in Fig. 3. As shown in Fig. 1 the fuel line 35 may have a numberA of turns' 36 Wrapped around the casing and in intimate metal to metal contact therewith so that fuel from a source of supply will enter the lowermost of such turns and be heated and pass `from the uppermost turn to the burner.

In order that air may be supplied for supporting combustion as shown in Fig. 1 a downdraft tube 37 may be disposed within the casing 10. The upper end of this downdraft tube extends through the opening 3S in the upper portion af a T-coupling 39 on the casing 16. The casing 10 has a ange 40 which butts against a ilange 41 on the T-couplng 39 and bolts 42 are employed for fastening the parts in assembled relation. The opening 38 in the top of the T-coupling preferably is of a size to accommodate the downdraft tube which can be inserted thereinto without dilculty. To maintain the lower end of the tube in convenient position above the burner so that air may properly be supplied through the burner some holding or fastening means is desirable and will be subsequently described.

Preheating of the air admitted through the downdraft tube is advisable in order to obtain maximum eiciency from the consumption of oil or fuel, and to increase the length of the path along which the air travels down the tube a baille is employed in the form of a spiral ribbon 43, the coils of such ribbon being normally slightly larger than the internal diameter of the pipe 37 so that when the coil is forced into the pipe a tight ht will be obtained yon account of the fact that the coil was slightly oversize. As illustrated, this coil may extend from one end of the pipe 37 to the other or be of any desired length.V

It is desirable that the bottom of the coil project beneath the lower end of thejpipe 37 and be provided with a constricted portion 44 with an opening so that the end of the coil may rest around the knob or boss 31 of a burner, so that the proper relation of the air intake pipe and the burner is maintained. The baffle being in direct heat exchange with the tube will be heated to cause the air to travel in a spiral or helical path to the burner where combustion occurs and air admitted through the openings 22 in the bottom of the casing is heated and discharged through the right and left openings in the T-coupling 39 into the tlues 45 and 46. These fiues 45 and 46 conduct the heated air through the area of the barn to be heated and thence to a smoke stack 47A through which the products of combustion are discharged.

As shown in Fig. 3 a horizontal casing is employed and consequently the downdraft tube 37' is slightly shorter than in Fig. l, as is also the case with the spiral ribbon balile 43. In Fig. 3 there is no preheating of the fuel. Preheating of the fuel however, can be accomplished in the manner disclosed in Figs. 2 and 4.

In Figs. 2 and 4 the same horizontal casing is employed and a burner corresponding to that of the burner illustrated in Figs. l and 3 likewise employed except as previously indicated, the burner has a tapered opening in its center at the top and is `held in place by rivets or other fastening elements 3 3 in the bottom. Fuel is supplied to this burner through a fuel pipe and bale 35' including coils 47 and an axially disposed lower end 48 with a tapered extremity 49. The coils 47 are likewise slightly oversize so that when they are forcedpinto the downdraft tube 37' there will be 'a tight tit and provide good metal to metal contact. Friction lit between the lower tapered end 49 of the axial portion 48 of this pipe and the tapered opening 32 of the burner will maintain the proper relation of the parts in the manner previously described. Also in this type of structure the coils 47 and pipe 35 shown in Figs. 2 and 4 serve as a battle and a fuel supply line and air entering the downdraft tube 37 will be preheated in passing through'the burner and caused to travel in a substantially spiral or helical path to the burner.

It will be obvious to those skilled in theart that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is shown in the drawing and described in the specification but only as indicated in the appended claims.

.What is claimed is:

l. In a tobacco eurer, a supporting base, an upright cylindrical casing mounted on said base and having air inlet openings in its bottom portion, a variable orifice burner in the bottoni portion of said casing and having an upstanding central projection and divergent burner openings, a drip pan beneath said burner, a fuel supply line connected to said burner and havnig a pre-heating coil disposed around said casing in intimate contact therewith, an air line for supplying air to the burner for supporting combustion within said casing, said air line including an air-intake tube disposed concentrically in said casing and providing a downdraft for air admitted to said casing adjacent the upper surface of said burner, a coupling for connecting the upper end of said casing with ues providing heat dissipating surfaces in a heating system, said coupling having an opening in which said air intake tube is located, a spiral ribbon-like baffle within said air-intake tube intimately engaging the same and having its lower end of gradually reduced diameter and engaging the projection on said burner and maintaining said burner and tube in predetermined spaced relation whereby fuel flowing through said coil is kboth agitated and pre-heated to facilitate vaporization thereof at said burner and combustion air admitted through said airintake tube is caused to follow a spiral path and have its temperature raised so that when mixed with the fuel and burned maximum eiciency will be obtained.

2. In a tobacco eurer, a casing having air inlet openings, a Variable orifice burner in the bottom portion of said casing and having divergentburner openings, a fuel supply line connected to said yburner and having a pre-heating coil, an air line for supplying air to the burner for supporting combustion within said casing, said air line including an air-intake tube disposed concentrically in said casing and providing a downdraft for air admitted to said casing adjacent the upper surface of said burner, a coupling for connecting the upper end of said casing with ilues providing heat dissipating surfaces in a heating system, said coupling having an opening in which said air intake tube is located, a spiral baille within said air-intake tube intimately engaging the same and having its lower end engaging said burner and maintaining said burner and tube in predetermined spaced relation whereby fuel ilowing through said coil is pre-heated to facilitate vaporization thereof at said burner and combustion air admitted through said air-intake tube is caused to follow a spiral path and have its temperature raised so that when mixed with the fuel and burned maximum eiliciency will be obtained.

3. In a tobacco curer, a casing having air inlet openings, a variable oriilce burner in the bottom portion of said casing and having divergent burner openings, a fuel supply line connected to said burner and having a preheating coil, an air line for supplying air to the burner for supporting combustion within said casing, said air line including an air-intake tube in said casing and proyiding a downdraft for air admitted to said casing adjacent the upperl surface of said burner, a helical baille within said air-intake tube intimately engaging the same and having its lower end engaging said burner and maintaining said burner and tube in predetermined spaced relation whereby fuel ilowing through said coil is preheated to facilitate vaporization thereof and combustion air admitted through said air-intake tube is caused to follow a spiral path and have its temperature raised so that when mixed with the fuel and burned maximum efficiency will be obtained.

4. In a tobacco eurer, a casing, a burner in the bottom portion of said casing, a fuel supply line connected to said burner, an air line for supplying :air to the burner for supporting combustion within said casing, said air line including an air-intake tube in said casing and providing a downdraft for air admitted to said casing adjacent the upper surface of said burner, a spiral baille within said air-intake tube intimately engaging the same and having its lower end engaging said yburner and maintaining said burner and tube in predetermined spaced relation whereby combustion air admitted through said air-intake tube is caused to follow a spiral path and have its temperature raised so that when mixed with the fuel and burned maximum eillciency will be obtained.

5. In `a tobacco curer, a casing, a burner in the bottom portion of said casing, a fuel supply line connected to said burner, an :air line for supplying air to the burner for supporting combustion within said casing, said air line including an air-intake tube in said `casing providing a down draft for air admitted to said casing adjacent the upper surface of said burner, a baille within said air intake tube intimately engaging the same and having its lower end engaging said burner and maintaining said 6 burner and tube in predetermined spaced relation, said baille comprising a coil of resilient ribbon-like material, whereby combustion air `admitted through said air-intake tube has its temperature raised so that when mixed with the fuel increased efficiency will result.

6. The structure of `claim 5, the lower end of said baille coil being of gradually reduced diameter.

7. The structure of claim 5, a projection extending upwardly from the top4 of said burner and the lower terminal end of said baille coil extending around said projection and engaging same.

8. In .a tobacco curer, an upstanding casing, a iluid burner in thev bottom of said casing, means to supply combustible iluid to said burner, an air-intake tube mounted in said casing and projecting upwardly from said -burner with its upper end extending outwardly of said casing, a helical shaped spiral baille positioned in said air-intake tube and contacting the inner periphery thereof to cause the air passing downwardly in said tube to move in a helical path into close intimate contact with the burner and the burning iluid therefrom, said baille extending to the burner and supporting said air intake tube in a ilxed position Irelative to said burner to assure a proper and continuous supply of air for combustion to said Iburner and the iluid being blnned therein.

9. The invention according to claim 8 in which the spiral baille is a conduit which carries the iluid for combustion to the burner.

10. T-he invention according to claim 8 -in which the baille includes a thin sheet material helix and a tubular conduit of a helical formation in which the pitch of the tubular conduit and of the sheet metal baille is the same whereby the incoming air is caused to move in a helical path.

11. The invention according to claim 8 in which the diameter of the helical shaped baille is progressively reduced froml the end of the air intake tube to the burner.

References Cited in the le of this patent UNITED STATES PATENTS 411,844 Wackerman Oct. 1, 1889 926,300 Stubbers June 29, 1909 1,024,261 Huston Apr. 23, 1912 1,440,562 Slayter Jan. 2, 1923 1,654,659 Mollvaine Jan. 3, 1928 2,185,886 Caldwell Jan. 2, 1940 2,453,233 Kittrell Nov. 9, 1948 2,547,841 Strickland Apr. 3, 1951 2,563,817 Carson Aug. 14, 1951 2,663,364 Dowless Dec. 22, 1953 2,682,300 Edwards June 29, 1954 FOREIGN PATENTS 1,020,220 France Nov. 12, 1952 19,287 Great Britain of 1913 1,075 Switzerland June 3, 1889 

